Funny bikes: a symmetrical study of urban space,vehicular units and mobility through the voyeuristic spokesperson of a video lens

This paper presents methodological considerations from a comparative, symmetrical video analysis of cyclist practices in Gothenburg and Toulouse. Video recording pays as much attention to the properties of bicycles as to the characteristics of people; it takes into account the pragmatic and situated dimension and, thus, allows a generalised symmetry. From there, visual methods enable us to submit the collected material to a double treatment of a quantitative analysis of observed bicycles and a qualitative ethnomethodological analysis of bike rental sequences. To better understand the logic and challenges of our method, we present it alongside an analogy with a famous film equivalent – the strategy used by the film-maker Michael Haneke in his heuristic film(s), Funny Games. Despite objectives and content that are obviously completely at odds to one another, the Funny Games film(s) and our own videos share at least five interesting features: twin films, static shots, photomontage, silent films, and rewinding.     

The front end in non-assembled product development: A multiple case study of mineral- and metal firms

We conceptualize the front end in non-assembled product development to be iterative and experiment-based, consisting of three sub-phases: informal start-up, formal idea-study, and formal pre-study. Although some key activities are shared with the front end activities in assembled product development, literature reviews, anticipating requirements of customers’ production processes, analysis of raw materials, anticipation of scale-up problems, and tests in bench-, pilot plant-, and full scale production represent unique activities. In addition, product concepts were frequently developed in parallel, requiring specification of physical, chemical and structural properties. These findings have implications for increasing the success and quality of front end efforts.     

Using ranked set sampling with binary outcomes in cluster randomized designs

We study the use of ranked set sampling (RSS) with binary outcomes in cluster-randomized designs (CRDs), where a generalized linear mixed model (GLMM) is used to model the hierarchical data structure involved. Under the GLMM-based framework, we propose three different approaches to estimate the treatment effect, including the nonparametric (NP), maximum likelihood (ML) and pseudo likelihood (PL) estimators. We investigate their asymptotic properties and examine their finite-sample performance via simulation. Based on these three RSS estimators, we further develop procedures for testing the existence of the treatment effect. We examine the power and size of our proposed RSS tests and compare them with existing tests based on simple random sampling (SRS). All the proposed RSS estimation and test methods are illustrated with two data examples, one for rare events and the other for non-extreme events. Throughout our investigations, we also consider the possible effect of imperfect ranking. Among the proposed methods, we provide recommendations on whether to use RSS rather than SRS with binary outcomes in CRDs and, if yes, when to use which RSS method. The Canadian Journal of Statistics 48: 342–365; 2020 © 2019 Statistical Society of Canada     

A note on the representation of {E\left({\textit{\textbf {x}}}\otimes {\textit{\textbf {xx}}}^{\prime}\right) } and {E\left({\textit{\textbf {xx}}}^{\prime }\otimes {\textit{\textbf {xx}}}^{\prime }\right)} for the random vector x

In this paper we consider ${E(x\otimes xx^{\prime})}$ and ${E(xx^{\prime }\otimes xx^{\prime})}$ for a random vector x where x _i has existing moments up to the fourth order and where the higher moments may depend on i. This extends previous results which assumed a common higher moment and E(xx??)?=?I.     

Vegetation changes at sub-xeric urban forest edges in Finland – the effects of edge aspect and trampling

The relative strengths of the effects of forest edges and recreational use on understorey vegetation were studied at sub-xeric boreal urban forest edges in the greater Helsinki region, Finland. The study was performed at northern, eastern, southern and western edges, and vegetation sample plots were placed on, next to and away from paths with different trampling intensities 0–107 m from the forest edges. We found that human trampling altered vegetation more than the effects of forest edges. Vegetation changed dramatically on paths and the effects of path edges were seen in seemingly untrampled vegetation at least up to 4 m from the path edge. However, our results suggested that the effect of the edge may penetrate up to 50 m into forest interiors. Changes in vegetation composition indicated that the effects of the edge were stronger at eastern, southern and western than at northern edges.     

The matrix affects carabid beetle assemblages in linear urban ruderal habitats

Matrix contrasts affect communities in patchy landscapes by influencing resources, abiotic conditions and spill-over effects. However, current knowledge is significantly biased towards forest and rural communities. We examined the effects of three different matrix types, i.e., low, intermediate and high contrasts, on carabid beetle assemblages at urban railway verges in two climatic regions. Study sites were located in Finland and in Slovenia. Using pitfall trapping, non-metric multidimensional scaling and generalised linear mixed models, we investigated carabid assemblages at railway verges and in differently contrasting adjacent matrices, i.e. built-up, grassland and forest. The matrix influenced carabid assemblages at railway verges. Assemblages grouped with adjacent matrix types, although some Finnish railway assemblages included a characteristic set of open dry habitat species. Abundances of generalist species at railway verges were higher when next to grassland or forest than urban matrices. Habitat specialists responded negatively to high contrast matrices, resulting in lower abundances of open habitat specialists in railway verges when next to forests and nearly no spill-over of forest specialists into railway verges. These patterns were consistent in both countries, i.e. irrespective of climatic region. Our study emphasises effects of the adjacent matrix and matrix contrasts on communities in linear open habitat patches in cities. Knowledge on matrix effects in patchy landscapes, such as urban environments, is essential in understanding the distribution and composition of communities in discrete patches. This knowledge can be used in conservation planning. If habitat specialists are negatively affected by high matrix contrasts, high contrasts should be avoided.     

Stratified Gaussian graphical models

Gaussian graphical models represent the backbone of the statistical toolbox for analyzing continuous multivariate systems. However, due to the intrinsic properties of the multivariate normal distribution, use of this model family may hide certain forms of context-specific independence that are natural to consider from an applied perspective. Such independencies have been earlier introduced to generalize discrete graphical models and Bayesian networks into more flexible model families. Here, we adapt the idea of context-specific independence to Gaussian graphical models by introducing a stratification of the Euclidean space such that a conditional independence may hold in certain segments but be absent elsewhere. It is shown that the stratified models define a curved exponential family, which retains considerable tractability for parameter estimation and model selection.     

Can job insecurity be managed? Evaluating an organizational-level intervention addressing the negative effects of restructuring

Although downsizing and reorganisation are recognised as serious threats to the psychological well-being of employees, intervention strategies for addressing these events are limited. This study evaluated the effects of a participatory organisational-level intervention in which employees and managers chose to address the psychosocial consequences, specifically job insecurity, of restructuring. The intervention was conducted among postal service letter carriers in Denmark and was evaluated based on quantitative and qualitative data. Using interviews (N?=?24) and observations, the programme theory of the intervention and to what extent the intervention had been implemented were assessed. Using survey data (N?=?238), repeated measures ANOVAs were conducted to test for differences in the development of job insecurity between the intervention group and a comparison group. The results indicate that the intervention group had a significantly smaller increase in one dimension of job insecurity as compared to the comparison group. Therefore, we conclude that employees’ experiencing of job insecurity, which typically follows in the wake of restructuring, can be addressed by planned efforts at the workplace level.     

Subjective Well-Being and Social Production Functions

Recent reviews of scientific work on subjective well-being (SWB) reveal disagreements in conceptualization, measurement, and explanation of the concept. We propose Social Production Function theory as a framework to resolve them. Social Production Function (SPF) theory integrates strengths of relevant psychological theories and economic consumer/household production theories, without their limitations (namely, tradeoffs between satisfaction of different needs are not in the first, and goals or needs are not in the second). SPF theory identifies two ultimate goals that all humans seek to optimize (physical well-being and social well-being) and five instrumental goals by which they are achieved (stimulation, comfort, status, behavioural confirmation, affection). The core notion of SPF theory is that people choose and substitute instrumental goals so as to optimize the production of their well-being, subject to constraints in available means of production. SPF theory guides research measurement and explanatory models, and it integrates features of contemporary subjective well-being theories.     

Dynamic path analysis—a new approach to analyzing time-dependent covariates

In this article we introduce a general approach to dynamic path analysis. This is an extension of classical path analysis to the situation where variables may be time-dependent and where the outcome of main interest is a stochastic process. In particular we will focus on the survival and event history analysis setting where the main outcome is a counting process. Our approach will be especially fruitful for analyzing event history data with internal time-dependent covariates, where an ordinary regression analysis may fail. The approach enables us to describe how the effect of a fixed covariate partly is working directly and partly indirectly through internal time-dependent covariates. For the sequence of times of event, we define a sequence of path analysis models. At each time of an event, ordinary linear regression is used to estimate the relation between the covariates, while the additive hazard model is used for the regression of the counting process on the covariates. The methodology is illustrated using data from a randomized trial on survival for patients with liver cirrhosis.